A wheelchair or other invalid carriage which is provided with an electric battery powered motor commonly includes a drive transmission mechanism, such as a gear train, which, while engaged with the driven wheel generates considerable resistance to rotation or drag while the motor is non-operational. It is highly advantageous consequently, to provide a drive mechanism which may be disengaged from the driven wheel at will to allow the wheelchair to be readily mobile while the motor is switched off.
Drive mechanisms for motorized wheelchairs, which include means for disconnecting the motor and the driven wheel have been proposed heretofore. However, the present invention offers advantages over devices which have previously been provided, as will hereinafter be explained.